| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| |
| package org.apache.sysds.hops.rewrite; |
| |
| import java.util.ArrayList; |
| |
| import org.apache.sysds.common.Types.OpOp1; |
| import org.apache.sysds.common.Types.OpOpData; |
| import org.apache.sysds.common.Types.OpOpN; |
| import org.apache.sysds.hops.DataOp; |
| import org.apache.sysds.hops.FunctionOp; |
| import org.apache.sysds.hops.Hop; |
| import org.apache.sysds.hops.NaryOp; |
| import org.apache.sysds.hops.UnaryOp; |
| |
| /** |
| * This rewrite is a general-purpose cleanup pass that removes any |
| * dangling parent references in one pass through the hop DAG. These |
| * dangling references could have been introduced by rewrites that |
| * remove operators but miss a proper cleanup. |
| * |
| */ |
| public class RewriteRemoveDanglingParentReferences extends HopRewriteRule |
| { |
| @Override |
| public ArrayList<Hop> rewriteHopDAGs(ArrayList<Hop> roots, ProgramRewriteStatus state) { |
| if( roots == null ) |
| return null; |
| |
| int numRm = 0; |
| for( Hop h : roots ) |
| numRm += removeDanglingParentReferences( h, false ); |
| |
| if( LOG.isDebugEnabled() && numRm > 0 ) |
| LOG.debug("Remove Dangling Parents - removed "+numRm+" operators."); |
| |
| return roots; |
| } |
| |
| @Override |
| public Hop rewriteHopDAG(Hop root, ProgramRewriteStatus state) { |
| if( root == null ) |
| return root; |
| |
| //note: the predicate can have an arbitrary root node |
| //and hence, we pin this node to prevent its removal |
| int numRm = removeDanglingParentReferences( root, true ); |
| |
| if( LOG.isDebugEnabled() && numRm > 0 ) |
| LOG.debug("Remove Dangling Parents - removed "+numRm+" operators."); |
| |
| return root; |
| } |
| |
| private int removeDanglingParentReferences( Hop hop, boolean pin ) { |
| //check mark processed |
| if( hop.isVisited() ) |
| return 0; |
| |
| //mark node itself as processed (because it's reachable over parents) |
| hop.setVisited(); |
| |
| //process parents recursively (w/ potential modification) |
| int count = 0; |
| for( int i=0; i<hop.getParent().size(); i++ ) { |
| Hop p = hop.getParent().get(i); |
| count += removeDanglingParentReferences(p, false); |
| i -= hop.getParent().contains(p) ? 0 : 1; //skip back |
| } |
| |
| //process node itself and children recursively |
| ArrayList<Hop> inputs = hop.getInput(); |
| if( !pin && hop.getParent().isEmpty() && !isValidRootNode(hop) ) { |
| HopRewriteUtils.cleanupUnreferenced(hop); |
| count++; |
| } |
| for( int i=0; i<inputs.size(); i++ ) |
| count += removeDanglingParentReferences(inputs.get(i), false); |
| |
| return count; |
| } |
| |
| private static boolean isValidRootNode(Hop hop) { |
| return (hop instanceof DataOp && ((DataOp)hop).isWrite()) |
| || (hop instanceof UnaryOp && ((UnaryOp)hop).getOp()==OpOp1.STOP) |
| || (hop instanceof UnaryOp && ((UnaryOp)hop).getOp()==OpOp1.PRINT) |
| || (hop instanceof UnaryOp && ((UnaryOp)hop).getOp()==OpOp1.ASSERT) |
| || (hop instanceof NaryOp && ((NaryOp)hop).getOp()==OpOpN.PRINTF) |
| || (hop instanceof FunctionOp) |
| || (hop instanceof DataOp && ((DataOp)hop).getOp()==OpOpData.FUNCTIONOUTPUT); |
| } |
| } |